A guest blog by Professor Paul Bennett, Director of Canterbury Archaeological Trust from 1984 to 2020.
In the mid-1160s, when Thomas Becket was Archbishop of Canterbury, a map was drawn of the Cathedral and its surrounding Benedictine Priory buildings to show a newly built aqueduct and its structures within and outside the city walls. This unique map, probably made on the orders of Prior Wibert (1151-67) who had installed the waterworks, is now bound into the great 12th century Canterbury (Eadwine) Psalter which has been at Trinity College, Cambridge since the end of the 16th century (MS R. 17.1).
Although the waterworks plan was first published by the Society of Antiquaries of London in 1755 and known to local antiquaries such as William Gosling (1696-1777) and Edward Hasted (1732-1812), it was not studied in detail until 1867. It was at this time that the polymath the Rev. Professor Robert Willis (1800-1875) traced the map, together with a smaller more naïve drawing of the water system, commented upon and published them in his pioneering survey of surviving precinct buildings, in Archaeologia Cantiana VII for 1868.
The provision of running water
Although bathing was discouraged by the Benedictine order, who considered it an unnecessary luxury, except for those in the infirmary, monastic regulations instructed that a routine of washing at the beginning of each day and before meals should be enforced. To this end, in the 1160s, Prior Wilbert set about providing Christ Church Priory with a sophisticated aqueduct bringing fresh water through lead pipes from a pond fed by springs about one mile north of the cathedral in what is now Old Park. With a fall of 10m from the conduit house to the precinct, it has been estimated that 10,000 litres of fresh, filtered water was transferred under pressure to the precincts every hour and circulated around the conventual buildings by an elaborate system of pipes and water towers. It was a continuous supply of fresh water, feeding elaborate basins, baths, latrines, kitchens, a bakehouse, a brewhouse and a fishpond, that must have filled parts of the precinct with a gentle background noise of running water. Greywater and rainwater were also used to continuously flush the monastic latrines, to be discharged into the city ditch through a Great Drain underlying the Service Court (Green Court), and from the city ditch to the river Stour.
The Waterworks Plan
The waterworks plan is bound into the psalter with east to the bottom of the page, but the drawing is meant to be viewed with south to the top. A guide to orientation is provided for the viewer in red capitals at the base of the drawing and on the right and left-hand sides. The southern side of the drawing (top) was cropped for binding with orientation lettering and other details lost.
The plan is drawn in ink and colour-coded throughout to show the difference between mains supply pipes (green), feeder pipes (red) and storm water drains (brown). The cathedral church and monastic buildings are depicted in surprising detail, with accuracy of orientation and relative positioning, using colour to distinguish between lead and tiled roofs. Windows, doors and distinctive fixtures and fittings are shown to add character, authority, and distinctiveness to the drawing and to individual buildings.
Surrounding topographical features, including city and priory walls, gates, intra-mural street, and ponds are also shown with colour. The map is annotated with Latin inscriptions which give both the name of the major buildings and explain details in the waterworks system.
The buildings are drawn to reveal where the pipes were located, the position of purge-pipes and stop cocks, and the direction of flow to allow the pipes, culverts and drains to be located should they require repair or replacement. The waterworks plan was therefore a technical drawing, produced by a skilled draughtsman, working in concert with a hydraulics specialist, to provide accurate details of the system and sufficient topographical indicators to understand the hydraulics, and locate individual elements of the system for purposes of maintenance.
In terms of the history of map-making the Wilbert’ drawing represents much more than the record of an elaborate aqueduct; it is one of the earliest plans of a Benedictine House, with a host of small and intimate details that supplement our knowledge of one of the largest and best documented monasteries in Britain.
There is much one can say about the gravity-fed supply, the depictions of the conventual buildings and the prior builder who organised the supply, but for this blog I will constrain my enthusiasm for the drawing with a few descriptions of the source of the supply, together with details of the washing basins in the Infirmary and Great cloister and the monastery fishpond.
Prior Wibert’s Waterworks plan of 1165 is a remarkable document. Not only does it provide a detailed view of the Cathedral Church and the layout of the conventual buildings of Christ Church Priory, but it provides an accurate survey of a complex aqueduct and gravity-fed piped water system that survived, with numerous additions into the late 19th century. Equally remarkable, is the fact that with perhaps modest work the Wibert supply could be made to flow again, to provide the precincts of Canterbury Cathedral with gravity-fed spring water from an original source of supply established 850 years ago!